Not sure what you're up against but I have a tabernacle for my Lancer 25. There's a pin that goes straight thru the mast, side to side , extending about 1" out each side. This is about 2" from the bottom. The tabernacle is bolted to the deck and has a J-shaped slot that the pin slides into. PM me your email and I'll send over some sketches. Also, my dad is new potentate of the shrine in Venice. We're coming down for the ball in a week and a half. I could swing by for a cup of coffee with free advice some morning if you like.
Don Scribner